<html lang="en">
	<head>
		<title>three.js webgpu - centroid sampling</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="main.css">
	</head>
	<style>

		body {
			margin: 0;
			overflow: hidden;
			width: 100vw;
			height: 100vh;
		}

		#demo {
			display: flex;
			flex-direction: row;
			align-items: center;
		}

		.renderer-wrapper {
			display: flex;
			flex-direction: column;
			align-items: center;
		}

		#antialiasing-disabled {
			border-right: 1px solid black;
		}

		canvas {
			width: 100%;
			height: 100%;
		}

	</style>
	<body>

		<div id="demo">
			<div id="antialiasing-disabled" class="renderer-wrapper">
				<div>antialiasing disabled</div>
			</div>
			<div id="antialiasing-enabled" class="renderer-wrapper">
				<div>antialiasing enabled</div>
			</div>
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.webgpu.js",
					"three/webgpu": "../build/three.webgpu.js",
					"three/tsl": "../build/three.tsl.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three/webgpu';
			import { varying, uv, texture, Fn } from 'three/tsl';

			import { Inspector } from 'three/addons/inspector/Inspector.js';

			let rendererAntialiasingEnabled;
			let rendererAntialiasingDisabled;
			let camera;
			let scene;
			let gui;

			const effectController = {
				sampling: 'normal'
			};

			const atlasCanvas = document.createElement( 'canvas' );
			atlasCanvas.width = 16;
			atlasCanvas.height = 16;

			const ctx = atlasCanvas.getContext( '2d' );
			ctx.fillStyle = 'red';
			ctx.fillRect( 0, 0, 8, 8 );

			const redUVs = [ 0, 1, 0.5, 1, 0.5, 0.5, 0, 0.5 ];
			ctx.fillStyle = 'green';
			ctx.fillRect( 8, 0, 8, 8 );

			const greenUVs = [ 1, 1, 0.5, 1, 0.5, 0.5, 1, 0.5 ];

			ctx.fillStyle = 'blue';
			ctx.fillRect( 0, 8, 8, 8 );

			const blueUVs = [ 0, 0, 0.5, 0, 0.5, 0.5, 0, 0.5 ];

			ctx.fillStyle = 'yellow';
			ctx.fillRect( 8, 8, 8, 8 );

			const yellowUVs = [ 1, 0, 0.5, 0, 0.5, 0.5, 1, 0.5 ];

			const faces = [ redUVs, greenUVs, blueUVs, yellowUVs ];

			const canvasTexture = new THREE.CanvasTexture( atlasCanvas );
			canvasTexture.colorSpace = THREE.SRGBColorSpace;
			canvasTexture.mapping = THREE.UVMapping;
			canvasTexture.wrapS = THREE.RepeatWrapping;
			canvasTexture.wrapT = THREE.RepeatWrapping;
			canvasTexture.magFilter = THREE.NearestFilter;
			canvasTexture.minFilter = THREE.NearestFilter;
			canvasTexture.format = THREE.RGBAFormat;
			canvasTexture.type = THREE.UnsignedByteType;

			const forceWebGL = false;

			init();

			function init() {

				camera = new THREE.PerspectiveCamera();
				camera.fov = 60;
				camera.near = 1;
				camera.far = 2100;
				camera.position.z = 50;

				scene = new THREE.Scene();

				const makeFaceGeometry = ( uvs ) => {

					const geometry = new THREE.BufferGeometry();
					const positions = [ - 1, - 1, 0, 1, - 1, 0, 1, 1, 0, - 1, 1, 0 ];
					geometry.setAttribute(
						'position',
						new THREE.BufferAttribute( new Float32Array( positions ), 3 )
					);

					const indices = [ 0, 1, 2, 2, 3, 0 ];
					geometry.setIndex( indices );

					geometry.setAttribute(
						'uv',
						new THREE.BufferAttribute( new Float32Array( uvs ), 2 )
					);

					return geometry;

				};

				const material = new THREE.MeshBasicNodeMaterial();
				const testUV = varying( uv(), 'testUV' );

				const createShader = ( type, sampling ) => {

					return Fn( () => {

						testUV.setInterpolation( type, sampling );

						return texture( canvasTexture, testUV ).rgb;

					} );

				};

				const withFlatFirstShader = createShader( THREE.InterpolationSamplingType.FLAT, THREE.InterpolationSamplingMode.FIRST );
				const withFlatEitherShader = createShader( THREE.InterpolationSamplingType.FLAT, THREE.InterpolationSamplingMode.EITHER );

				const withSampleShader = Fn( () => {

					testUV.setInterpolation( THREE.InterpolationSamplingType.PERSPECTIVE, THREE.InterpolationSamplingMode.SAMPLE );

					return texture( canvasTexture, testUV ).rgb;

				} );

				const withInterpolationShader = Fn( () => {

					testUV.setInterpolation( THREE.InterpolationSamplingType.PERSPECTIVE, THREE.InterpolationSamplingMode.CENTROID );

					return texture( canvasTexture, testUV ).rgb;

				} );

				const withoutInterpolationShader = Fn( () => {

					return texture( canvasTexture, uv() ).rgb;

				} );

				material.colorNode = withoutInterpolationShader();

				const faceMeshes = [];

				for ( let x = - 5; x < 5; x ++ ) {

					for ( let y = - 5; y < 5; y ++ ) {

						const face = faces[ Math.floor( Math.random() * faces.length ) ];
						const geometry = makeFaceGeometry( face );
						const mesh = new THREE.Mesh( geometry, material );
						mesh.position.set( x * 2, y * 2, 0 );
						faceMeshes.push( mesh );
						scene.add( mesh );

					}

				}

				// Create Standard Renderer
				rendererAntialiasingDisabled = new THREE.WebGPURenderer( {
					antialias: false,
					forceWebGL: forceWebGL
				} );

				rendererAntialiasingDisabled.setPixelRatio( window.devicePixelRatio );
				rendererAntialiasingDisabled.setSize( window.innerWidth / 2, window.innerHeight );
				rendererAntialiasingDisabled.setAnimationLoop( animateStandard );

				// Create antialiased renderer
				rendererAntialiasingEnabled = new THREE.WebGPURenderer( {
					antialias: true,
					forceWebGL: forceWebGL
				} );

				document.body.querySelector( '#antialiasing-enabled' ).appendChild( rendererAntialiasingEnabled.domElement );
				rendererAntialiasingEnabled.setPixelRatio( window.devicePixelRatio );
				rendererAntialiasingEnabled.setSize( window.innerWidth / 2, window.innerHeight );
				rendererAntialiasingEnabled.setAnimationLoop( animateAliased );
				rendererAntialiasingEnabled.inspector = new Inspector();

				document.body.querySelector( '#antialiasing-disabled' ).appendChild( rendererAntialiasingDisabled.domElement );
				document.body.querySelector( '#antialiasing-disabled' ).appendChild( rendererAntialiasingDisabled.domElement );

				onWindowResize();

				window.addEventListener( 'resize', onWindowResize );

				gui = rendererAntialiasingEnabled.inspector.createParameters( 'Settings' );
				gui.add( effectController, 'sampling', [
					THREE.InterpolationSamplingMode.NORMAL,
					THREE.InterpolationSamplingMode.CENTROID,
					THREE.InterpolationSamplingMode.SAMPLE,
					'flat first',
					'flat either'
				] ).onChange( () => {

					const interpolationShaderLib = {
						[ THREE.InterpolationSamplingMode.NORMAL ]: withoutInterpolationShader,
						[ THREE.InterpolationSamplingMode.CENTROID ]: withInterpolationShader,
						[ THREE.InterpolationSamplingMode.SAMPLE ]: withSampleShader,
						[ 'flat first' ]: withFlatFirstShader,
						[ 'flat either' ]: withFlatEitherShader
					};

					const shader = interpolationShaderLib[ effectController.sampling ];

					for ( let i = 0; i < faceMeshes.length; i ++ ) {

						faceMeshes[ i ].material.colorNode = shader();
						faceMeshes[ i ].material.needsUpdate = true;

					}


				} );

			}

			function onWindowResize() {

				const halfWidth = window.innerWidth / 2;
				rendererAntialiasingDisabled.setSize( halfWidth, window.innerHeight );
				rendererAntialiasingEnabled.setSize( halfWidth, window.innerHeight );
				const aspect = ( halfWidth ) / window.innerHeight;

				camera.aspect = aspect;
				camera.updateProjectionMatrix();

			}

			function animateStandard() {

				rendererAntialiasingDisabled.render( scene, camera );

			}

			function animateAliased() {

				rendererAntialiasingEnabled.render( scene, camera );

			}

		</script>
	</body>
</html>
